It is desirable to control the safety of, for example, hazardous machines in a workshop environment. For machine safety, it is desirable that locks except for manual operability also can be remote-controlled (electrical operability) and monitored. In these cases, the lock device should be kept locked from the outside during the time when, for example, a hazardous machine in the locked area is running, at the same time as the lock device can be opened from the inside.
Certain kinds of lock devices involve adaptation for industrial applications and to manage rough environments. In safety applications, such as gates surrounding hazardous machines, such a device should keep a door locked even at energy drop-out (that is, energy should be applied in order to unlock the door).
DE 196 32 962 refers to a switch and a door system. The system includes two handles, an inner and an outer handle, which are coupled together through a pin, and an elongated key-like actuator. The system further includes a gear rack section provided with a gear drive section cooperating with the pin in a longitudinal direction of the housing in communication with the actuator.